This class acts as a pointer which will automatically become null if the object to which it points is deleted. More...

Classes
class	Master
	This class is embedded inside an object to which you want to attach WeakReference pointers. More...

class	SharedPointer
	This class is used internally by the WeakReference class - don't use it directly in your code! More...

Public Types
typedef ReferenceCountedObjectPtr< SharedPointer >	SharedRef

Public Member Functions
	WeakReference () noexcept
	Creates a null SafePointer. More...

	WeakReference (ObjectType *const object)
	Creates a WeakReference that points at the given object. More...

	WeakReference (const WeakReference &other) noexcept
	Creates a copy of another WeakReference. More...

WeakReference &	operator= (const WeakReference &other)
	Copies another pointer to this one. More...

WeakReference &	operator= (ObjectType *const newObject)
	Copies another pointer to this one. More...

	WeakReference (WeakReference &&other) noexcept

WeakReference &	operator= (WeakReference &&other) noexcept

ObjectType *	get () const noexcept
	Returns the object that this pointer refers to, or null if the object no longer exists. More...

	operator ObjectType * () const noexcept
	Returns the object that this pointer refers to, or null if the object no longer exists. More...

ObjectType *	operator-> () noexcept
	Returns the object that this pointer refers to, or null if the object no longer exists. More...

const ObjectType *	operator-> () const noexcept
	Returns the object that this pointer refers to, or null if the object no longer exists. More...

bool	wasObjectDeleted () const noexcept
	This returns true if this reference has been pointing at an object, but that object has since been deleted. More...

bool	operator== (ObjectType *const object) const noexcept

bool	operator!= (ObjectType *const object) const noexcept

Detailed Description

template<class ObjectType, class ReferenceCountingType = ReferenceCountedObject>
class WeakReference< ObjectType, ReferenceCountingType >

This class acts as a pointer which will automatically become null if the object to which it points is deleted.

To accomplish this, the source object needs to cooperate by performing a couple of simple tasks. It must embed a WeakReference::Master object, which stores a shared pointer object, and must clear this master pointer in its destructor.

E.g.

class MyObject
{
public:
    MyObject()
    {
        // If you're planning on using your WeakReferences in a multi-threaded situation, you may choose
        // to create a WeakReference to the object here in the constructor, which will pre-initialise the
        // embedded object, avoiding an (extremely unlikely) race condition that could occur if multiple
        // threads overlap while creating the first WeakReference to it.
    }
    ~MyObject()
    {
        // This will zero all the references - you need to call this in your destructor.
        masterReference.clear();
    }
private:
    // You need to embed a variable of this type, with the name "masterReference" inside your object. If the
    // variable is not public, you should make your class a friend of WeakReference<MyObject> so that the
    // WeakReference class can access it.
    WeakReference<MyObject>::Master masterReference;
    friend class WeakReference<MyObject>;
};
// Here's an example of using a pointer..
MyObject* n = new MyObject();
WeakReference<MyObject> myObjectRef = n;
MyObject* pointer1 = myObjectRef;  // returns a valid pointer to 'n'
delete n;
MyObject* pointer2 = myObjectRef;  // returns a null pointer

See also: WeakReference::Master